Diamond drilling bits



March 13, 1956 w. M. KOCH 2,738,166

DIAMOND DRILLING BITS 4 Sheets-Shed l Filed Oct. 15, 1952 W////am M.Koch INVENTOR.

BY 2. M 6A? M Ar a/m5 Ks W. M. KOCH DIAMOND DRILLING BITS March 13, 19564 Sheets-Sheet 2 Filed Oct. 15, 1952 WET-l W////G/77 M. Koc

INVEN ggm ATTORNEYS March 13, 1956 w, M, KOCH 2,738,166

DIAMOND DRILLING BITS Filed Oct. 15, 1952 4 Sheets-Sheet 3 W////am M.Koch INVENTOR.

BY Z. M

KK/MML ATTORNEVJ March 13, 1956 Filed Oct. 15, 1952 W. M. KOCH DIAMONDDRILLING BITS 4 Sheets-Sheet 4 l V////a/77 M. Koo/2 INVENTOR.

ATTORNEYS United States Patent-O 2,738,166 DIAMOND DRILLING BITS WilliamMi Koch, -Houston,{lex-., .assignor to Read Roller This invention.relateslitoanewariduseful improvements in diamond drilling bits.

As is well known,.the usual diamond-drilhbits for-oil wells and-the likedonot satisfactorily cut the full diameterof the. well borer since thelineal 'surfacespeed near the center ofIthe bit. is too low.

An object of this invention, therefore, is'to providea diamond drill bitcapable of cutting the full diameter of a well bore, wherein said bithas an annular cuttingsurface which leaves a central uncut core, and anauxiliary cutter disposed within said bit to cut the central uncut coreat a suflicient lineal surface speed.

An important object of this invention is to provide a diamond drill bithavingan auxiliarycentral cutter which is capable of remainingstationary with respect to the bit for rotation therewith, or uponcontact with an uncut central core or the like, of being rotated aboutitsown axis, while said bit rotates relative thereto.

Another object ofthis invention isto provide a dia} mond bit having anannular cutting; surface which leaves a centraluncut core, andtanauxiliary central cutter connected to saidbit through anniversaljoint,whereby said auxiliary cutter rotates withJthe uncut core. a

The construction designedto carry out the invention will be hereinafterdescribed together with otherfeatures thereofi.

about its own axis upon contact The invention will be more readilyunderstood from a d reading of the following specification and byreference to the accompanying drawings forming a part thereof, whereinan example of the, invention is shown, and wherein:

' Figure 1 is a vertical view, partly in section and partly inelevation, illustrating one form of the diamond bit of ing rotation ofthe bit body whenno core is extending into contact with the cutter;

Figure 5 is a view similar to Figure sjbur illustrating therelativemovementof the bit body with respect to the cutter as well asthe rotational movement of the cutter about its own axis when suchcutter iscontacted by an uncut core;

"Figure 6 is a partial view in section of a modified form ofthe' bit'ofthis invention; and i Figure 7 is a plan rview of the shield used in theform ofthe invention shown inFigure 6 1 In the drawings, the numeral Adesignates the bit body which is composed of an adapter sub 10 and a bithead llconnected thereto by any suitable means such as threads 12. Theupper end of the adapter sub"10 has a'threadedbox 14 for connection withthe pin end of 2 v the drill stem which extendsto thesurface'of the.well. The bit body A has an axial-bore oropening 15 'which includes anupper portion 15a and a lower portion 15b which is of reduced diameteras compared to the upper portion 15a. At the lowervendof' the bitheadll, there is.:formed an annular cutting surface 16 which extendsalong the. bottom ofthe bit head and the outer sides thereof; as .wellas on,the inner wall of the axialopening 15b. Within the. enlarged-boreportion 15aof the axial bore,15, there ismounted an auxiliary cutter 17and .hasconnection with the bit body A through aconnecting means Bwhichprovides for universal jointaction. The annular surface 16 andthe-auxiliary cutter 17 together cut. the, full diameter of the ,borehole and; to this end, hard wearing inserts such as diamonds 16a and 17aare disposed on the cutting surfaces of the an? nular cutting surface116andthe auxiliary cutter 17, re-. spectively.

Referring now to Figure l, therein it can be seenthat the adapter sub 10of the bit body A has a central hub or spider 20 disposed withintheaxial boreof the bit body above the bit head 11. Thisspider 20 has mudor slush passages 21 disposed circumferentially thereabout. The lowerend of thespider 20 has a threaded socket 22 which receives athreadedpin 23 formed on the upper end of the universal connection B.

The universal connection .13 shown in Figure 1 is of conventionalconstruction and includes a clevis 24 extending from the pin 23 and. inwhich is mounteda sleeve 25 on a pin ,or shaft 26 which extends. throughshape with the portion oflargest diameter at the top thereof andconvergingintoa cylindrical projection 29 at the-lower end thereof. Theprojection 29 fits into a circular track 30 which has inclined walls 30aand 30b which are parallel to each other, and are of the sameinclination as; the angle 'of inclination of the longitudinal axis of-the cutter 17 with respect to the longitudinalaxis of the bit body A.The'track 30 and the projection 29 are slidablerelative to each other,whereby when the cutter 17 is held in one position with respect totheground, the track 30rnoves relative to such projection 29 duringrotation of the bit body A.

'Thetrack 30 has a plurality-of openings 31 which are ,below the track30 and which provide communication withthe slush passages 32 in theannular cutting surfaee =16. a y

In the operation ofthediamondbit of Figure l, the bit body A is rotatedthrough the rotation of the drill stem (notshown) which extends'tothewell surface in the usual manner. This rotation, ofcourse, imparts ro-'tationto the annular-surface '16'whereby an annular path is cut in thewell bore, leaving an uncut central core which extends'into thereduceddiameter portion 15b 0 the axial opening 15 in the bit body A.

The: uncut central core'formed' in'the axial opening 15b" will continueto beformed and will extendupwardly until it contacts the inclinedcutting face of the cutter 17 which extends across'the full diameter ofsuch opening-15b. Prior; tothe'time that'the uncut central coreactually:contacts' thecutter 17, thecutter 17 will be. rotating'withthebitiihead 11. The-relationship "of the'cutter 171to the bit head 11 canbestbe appreciated by considering FiguresS-S. Thus,'in Figure 3; thecutter 17. istshown before rotation is imparted to the'bitxbody Inuthisposition atselected'band'C on the cutter:17 is disposedover the axial:opening*'15b,--and theprojec Patented Mar. 13, 1956 3 tion 29 is locatedadjacent a selected point R on the track 30. When no core is contactingthe cutter 17, the cutter 17 simply rotates with the bit body A, butthereis no rotation of the cutter 17 about its own axis 17'. Thus, theentire movement of the cutter 17 would be about. the axis A of the bitbody A with the projection 29 remaining in the same position in thetrack 30 relative to the point R and with the band C on the cuttersurface remaining over the axial bore 15b. This can best be appreciatedby considering the movement of the bit from the position shown in Figure3 to that shown in Figure 4. It will also be appreciated that therewould be no movement of the universal connection B when moving from theposition shown in Figure 3 to that shown in Figure 4. Therefore, thecutter 17 may be said to be stationary with respect to the bit body A.

However, when a core X extends through the axial bore 15b and contactsthe circumferential cutting surface of the cutter 17, the core X thenprovides a reaction point or a resistance which prevents the projection29 on the cutter 17 from moving relative to the ground. Thus, if thecore X contacted the cutter 17 in the position shown in Figure 3 duringrotation of the bit body A, the projection 29 would remain stationaryrelative to the bottom of the well, that is, assuming the projection 29to be pointing north, it will remain pointing north even though thetrack 30 is rotated relative thereto. However, the rotation of the bitbody A and the track 30 effects a rotation of the cutter 17 about itsown axis 17 since the cutter 17 is directly connected to the bit body Athrough the universal joint B. As can be seen in Figure 5, a position isshown assuming that the cutter has revolved about its own axis 17'one-quarter revolution from that shown in Figure 3, whereby the band Chas moved one-quarter of a revolution and the point R on the track 30has moved one-quarter of a revolution with respect to the projection 29.By reason of this rotation of the cutter 17 about its own axis 17', anew cutting face is constantly being presented to the uncut central coreX which is in contact with the cutting surface of the cutter 17, therebyassuring equal and distributed wear on the cutting surface of the cutter17. Since the cutter 17 is cutting the uncut central portion X and theannular cutting surface 16 is cutting the remainder of the well borehole, it will be appreciated that the full diameter of the bore hole isthereby being cut and that satisfactory lineal speed is obtained withthe auxiliary cutter '17, as well as with the annular cutting surface16. The term lineal speed as herein employed, refers to the relativesurface speed between the auxiliary cutter 17, and the central uncutcore X which extends into the central opening of the drill bit.

In Figure 2, a modification of the diamond bit of this invention isillustrated, wherein all parts are substantially the same with theexception of the universal mounting or connection means B. In Figure 2the universal connection B includes a ball 35 which is mounted betweencurved sockets 36 and 33 in the plug 23 and cutter 17, respectively.Also, beveled gear teeth 37 are circumferentially disposed on the lowerend of the plug 23 and mating gear teeth 38 are provided on the upperend of the cutter 17, such gears 37 and 38 serving as the sole driveconnection between the cutter 17 and the bit body A.

The operation of the form of the diamond bit shown in Figure 2 will besubstantially the same as that shown in Figure 1 except that the cutter17 will be rotated about its own axis 17' when the cutting surfacethereof is in contact with an uncut central core X by reason of themeshing of the gear teeth 37 and 38, with the ball 35 serving as a pivotpoint for the cutter 17. Thus, in the form shown in Figure 2, the cutter17 would revolve about the longitudinal axis A of the bit body A butwould not rotate about its own axis when the uncut central core is notin contact with the cutter 17. However, when the core does contact thecutter 17 it then remains stationary with respect to the ground whilethe bit body A rotates relative thereto, and at the same time the cutter17 will rotate about its own axis 17' to provide a constantly changingcutting surface which abrades or otherwise cuts the uncut central coreextending through the bore 15b.

In Figure 6, another modification of the drill bit illustrated in Figure1 is shown. The bit of Figure 6 is identical with that shown in Figure 1except that a shield 40 is utilized in place of the trackway 30 ofFigure 1. The shield 40 is rotatable with respect to the bit head 11 andpreferably an anti-friction means such as the ball bearings 41 aredisposed circumferentially between the shield 40 and the bore portion15a of the bore 15 of the bit body. These bearings 41 may also serve tosupport the bottom surface 42 of the shield 40 slightly above and out ofcontact with the transverse surface of the bore 15, whereby frictionalengagement therebetween is prevented.

The shield 40 has an inclined cylindrical recess 43 therein for thereception of the cylindrical projection 29. The wall of the recess 43 isof the same angle of inclination as that of the cutter 17 and the walls30a and 30b of the trackway 30 shown in Fig. 1. It will be apparent thatwith the projection 29 in the recess 43, the shield 40 and the cutter 17must rotate together.

The shield 40 has a central bore 45 of substantially the same diameteras the lower bore 15b in the bit head 11 and such bore 45 forms acontinuation of the bore 15b up to the cutting surface 17a of the cutter17. The upper surface of the shield 40 is inclined and concavely curvedat 46 to correspond with the inclination and curvature of the cuttingsurface 17a of the cutter 17. This inclined curved surface 46 mergeswith walls of the recess 43 as best seen in Figure 7. The inclinedcurved surface 46 also is just slightly below the surface 17a of thecutter so that a core cut by the bit during rotation thereof, willextend upwardly through the bore 15b and the bore 45 until it contactsthe cutting surface 1711. Thus, the core is supported throughoutsubstantially its entire length and is thereby prevented from fracturingtransversely or otherwise into large pieces, thereby allowing the cutter17 to abrade the core at its upper end into the small pieces rather thanbreak it into large pieces which would be too large to be circulateddownwardly through the slush passages.

Circulation or washing away of the abraded pieces of the core iseffected through downwardly and outwardly inclined circular openings 48extending from the upper to the lower end of the shield 4.0, with thelower ends of the openings 43 communicating with the outer passage 32 inthe bit head 11. Triangular slots 49 may also be provided in the lowersurface 42 of the shield 40 in communication with the bore 45 thereofand the inner slush passages 32 of the bit head 11. It will beappreciated that the particular shape and inclination of the openings 48and slots 49 may be changed if desired.

The operation of the bit of Figure 6 is substantially identical withthat of Figure 1 except that the shield 49 remains fixed with respect tothe cutter 17 during the rotation of the bit head 11. Thus, as the coreX is initially fonned in the bore 15b, and before it contacts thesurface 17a of the cutter 17, the cutter 17 and shield 40 will rotatewith the bit head 11. When the core X contacts the surface 17a theresistance thereof prevents the cutter 17 and shield 40 from rotatingwith the bit head 11, but since the universal connection B is connectedto the bit body, rotation of the cutter 17 about its own axis iseffected while the bit body is rotated about its axis relative to thecutter 17. Thus, it can be seen that the same relative movement of thecutter 17 and the bit body is effected in the form shown in Figure 6 asin Figure 1.

It will be appreciated, of course, that other universal connections forconnecting the cutter 17 to the bit body A could be employed in place ofthe two forms illustrated herein.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction may be made, within the scope of the appended claimswithout departing from the spirit of the invention.

What is claimed is:

1. A diamond bit having a bit body with an annular cutting surface forcutting an annular path in a well bore leaving an uncut central core,said body having an axial central opening into which the uncut centralcore is adapted to extend, an auxiliary central cutter within said axialopening adapted to contact said uncut central core, an annular trackwithin said axial opening of said bit body, one end of said auxiliarycutter fiting into said track, and the other end of said auxiliarycutter being connected to said bit body through a universal connection,whereby upon contact of said cutter with the central uncut corerotational movement of said bit body effects a rotation of saidauxiliary cutter about its own axis.

2. The structure set forth in claim 1, wherein said annular track isformed in the bit body within said axial opening.

3. The structure set forth in claim 1, wherein annular track is aseparate member supported on said bit body within said axial opening.

4. In a bit having an axial bore, an auxiliary cutter disposed withinsaid bore at an angle to the longitudinal axis of said axial bore, saidauxiliary cutter being provided with an upper and a lower end, meansconnecting said auxiliary cutter with said bit including meansconnecting the lower end of said cutter to said bit for permitting thebit to rotate relative to said cutter when said cutter is in contactwith a material that is stationary with respect to said bit during therotation thereof, and including means connecting the upper end of saidcutter to said bit for transmitting the rotation of said bit to saidcutter for rotating said cutter about its own axis passing through saidends when said bit is rotated relative to said cutter.

5. In a bit having an axial bore, an auxiliary cutter disposed withinsaid bore at an angle to the longitudinal axis of said axial bore, saidauxiliary cutter being provided with an upper and a lower end, meansconnecting said auxiliary cutter with said bit including meansconnecting the lower end of said cutter to said bit for per- 6 mittingthe bit to rotate relative to said cutter when said cutter is in contactwith a material that is stationary with respect to said bit during therotation thereof, and and a universal connection connecting the upperend of said cutter to said bit for transmitting the rotation of said bitto said cutter for rotating said cutter about its own axis passingthrough said ends when said bit is rotated relative to said cutter.

6. In a bit having an axial bore, an auxiliary cutter disposed withinsaid bore at an angle to the longitudinal axis of said axial bore, saidauxiliary cutter being provided with an upper and a lower end, meansconnecting said auxiliary cutter with said bit including a projection onthe lower end of said cutter and an annular track within the bore ofsaid bit in which said projection is mounted for permitting the bit torotate relative to said cutter when said cutter is in contact with amaterial that is stationary with respect to said bit during the rotationthereof, and a universal connection connecting the upper end of saidcutter to said bit for transmitting the rotation of said bit to saidcutter for rotating said cutter about its own axis passing through saidends when said bit is rotated relative to said cutter.

7. A diamond bit having a bit body with an annular cutting surface forcutting an annular path in a well bore leaving an uncut central core,said body having an axial central opening into which the uncut centralcore is adapted to extend, an auxiliary central cutter within said axialopening, and means connecting said cutter to said bit body includingmeans connecting one end of said cutter to said bit body for permittingthe bit body to rotate about its axis and relative to the cutter whensaid cutter is in contact with said central uncut core, and a universaljoint connection including mating gears on said body and said cutterconnecting the other end of said cutter to said bit body fortransmitting the rotation of said bit body to said cutter for rotatingsaid cutter about its own axis when said bit body is rotated about itsaxis and relative to said cutter.

References Cited in the file of this patent UNITED STATES PATENTS1,482,397 Hansen Feb. 5, 1924 1,836,638 Wright et a1 Dec. 15, 19311,954,166 Campbell Apr. 10, 1934 2,024,730 Hammer Dec. 17, 19352,034,073 Wright Mar. 17, 1936

1. A DIAMOND BIT HAVING A BIT BODY WITH AN ANNULAR CUTTING SURFACE FORCUTTING AN ANNULAR PATH IN A WELL BORE LEAVING AN UNCUT CENTRAL CORE,SAID BODY HAVING AN AXIAL CENTRAL OPENING INTO WHICH THE UNCUT CENTRALCORE IS ADAPTED TO EXTEND, AN AUXILIARY CENTRAL CUTTER WITHIN SAID AXIALOPENING ADAPTED TO CONTACT SAID UNCUT CENTRAL CORE, AN ANNULAR TRACKWITHIN SAID AXIAL OPENING OF SAID BIT BODY, ONE END OF SAID AUXILIARYCUTTER FITING INTO SAID TRACK, AND THE OTHER END OF SAID AUXILIARYCUTTER BEING CONNECTED TO SAID BIT BODY THROUGH A UNIVERSAL CONNECTION,WHEREBY UPON CONTACT OF SAID CUTTER WITH SAID CENTRAL UNCUT COREROTATIONAL MOVEMENT OF SAID BIT BODY EFFECTS A ROTATION OF SAIDAUXILIARY CUTTER ABOUT ITS OWN AXIS.